Does Hawaii really have interstate highways?

Yes — Hawaii is the only state with H-numbered interstates: H-1, H-2, and H-3, all on Oahu. They're built to interstate standards even though they can't touch another state, and Hawaii has no US highways at all.

How do mile markers work on Hawaii's islands?

Each island numbers its own routes, and mile markers restart per route per island. On Maui's Road to Hana, the mile markers are the tourist directions — waterfalls and trailheads are given by mile marker rather than street address.

Does MileCheck have live Hawaii DOT alerts?

Yes. MileCheck pulls live road alerts for Hawaii — closures and work zones — tied to the mile marker. Mile markers cover Hawaii's highways on every island and work offline.

Highway Mile Markers in Hawaii

Hawaii's highways are unlike anywhere else in the country — interstates that can't reach another state, no US highways at all, and islands where the mile markers double as tourist directions. Here's how it all works, and how to see your exact marker plus live alerts in real time.

How Hawaii numbers its highways

Hawaii is the only state with H-numbered interstates: H-1, H-2, and H-3, all on Oahu. They're real interstate highways, built to the same standards as the mainland's — they just happen to be surrounded by the Pacific. There are no US highways in Hawaii; everything else is a state route, and each island numbers its own. Mile markers restart per route per island, so "mile marker 24" only means something once you know which road and which island. Mile marker data for Hawaii's highways is bundled into MileCheck and works offline.

The corridors people actually drive

H-1 is Oahu's spine, running from Kalaeloa past Pearl Harbor and the airport through downtown Honolulu to Kahala.
H-2 heads north from the H-1 toward Wahiawa; H-3 crosses the Koolau Range to Kaneohe through one of the most scenic tunnels in America.
On Maui, the Hana Highway (Routes 36 and 360) winds the famous Road to Hana; on the Big Island, Route 11 and Route 19 circle the island through Kona and Hilo.

Where mile markers matter most: the Road to Hana

On Maui's Road to Hana, the mile markers are the directions. Guidebooks and locals alike give every waterfall, banyan tree, and trailhead by marker — "the falls just past MM 24," "the black sand beach near MM 32." There are no addresses out there, and the road has more curves than cell bars. Knowing exactly which marker you're at is the difference between finding the trailhead and driving past it twice.

H-1 runs the length of urban Oahu, from Kalaeloa past Pearl Harbor and downtown Honolulu to Kahala — an interstate that will never touch another state.

Rain, rockfall, and one-road-in coastlines

Hawaii's hazards are tropical rather than icy: heavy rain that floods low crossings, rockfall and landslides on the coastal cliff roads, and the occasional lava-adjacent closure on the Big Island. On roads like the Hana Highway or Kauai's north shore, there's often exactly one way in and one way out — so a single closure, announced by mile marker, changes the whole day's plan.

Live Hawaii DOT alerts, in one place

MileCheck pulls live road alerts for Hawaii — closures and work zones, tied to the mile marker — so you can see what's ahead before you commit to the coast road. Mile markers cover Hawaii's highways on every island.

Everyday and emergency

Whether you're hunting a waterfall past MM 24 on the Road to Hana, reporting a breakdown on the H-3, or telling a friend which marker the beach pull-off is at, the mile marker is the location Hawaii's roads run on. MileCheck shows yours in real time, down to a tenth of a mile, even where the cell signal drops behind a ridge — with CarPlay and Android Auto in the rental car.

Keep reading

More state guides: California

Essentials: What to tell 911 on the highway · How to find your mile marker · Browse the live mile marker map · All 50 states